Reviving this old thread as it seemed unresolved.
I had wondered if the Iodine API might have been of use. Iodine make use of the FDA drugs list. http://www.iodine.com/api
"A quick review of the terms of use
Give us credit. Wherever you display Iodine content, you must also link back to Iodine using the link supplied in the API. You must also give us credit, either by prominently displaying our logo or including text that says “Powered by Iodine” or similar. Also, you should never claim ownership, responsibility or sponsorship for Iodine Content.
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Be consumer-facing. You must obtain our prior written consent if you want to use Iodine information for non-consumer purposes.
Integrate us to add value. Do not use the API to recreate what Iodine’s own website or mobile apps already offer. If that’s what you’re after, simply link to Iodine or request deeper site integration.
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Leave our data and content alone. You may not alter our data or combine it with other data. You may not alter our logo, graphics, or Iodine Content.